A tidal power generator is generally an apparatus for generating power by using a rising tide and an ebb tide of the seawater, i.e., flow of bidirectional tidal currents. Principles similar to an overland aerogenerator are applied to the tidal power generator.
The overland aerogenerator generates power as an air blade rotates by using wind power, wherein the tidal power generates power as a blade rotates by using flow of the seawater.
Since the fluid density of seawater is 900 times or above the air density, the tidal power generator using seawater can generate more power than overland generators. However, components used in the tidal power generator must be formed of a corrosion resistant material having intensity high enough to overcome such high density and capable of enduring corrosion due to salt of seawater.
Accordingly, the blade used in the tidal power generator is heavy since it is formed of a corrosion resistant high strength alloy, and has low economic feasibility due to high material costs for manufacturing the blade.
In order to overcome such a problem, the blade is formed of a complex material using carbon fiber, glass fiber reinforced plastic (GFRP), or the like so that the blade is light, and has an integral structure from a hub to a tip of a rotor.
However, since it is difficult to manufacture the blade in an integral shape by using casting or any other processing method, it is not easy to mass produce the blade, and manufacturing costs increase.
Also, when a large blade is manufactured, it is difficult to manage manufacturing processes since quality and manufacturing processes of the entire large blade are affected when a local defect is generated.